First direct detection of H20 ice on asteroid

[Sam Fraser]

In the Main Belt, unfortunately:

Two teams of researchers independently verified that the asteroid 24 Themis – a large rock hurtling through space in the asteroid belt between Mars and Jupiter – is coated in a layer of frost.

http://www.space.com/scienceastronomy/water-ice-on-asteroid-100428.html

[JohnHunt]

I found something odd in the new report which went unaddressed but seemed glaring. The report said that the scientists didn't expect to find water on the surface because it should have evaporated / sublimated. ...and yet it was there. What gives???

[Rhyshaelkan]

Water-Ice if it is cold enough will not evaporate even in hard vacuum. Liquid-Water is over that certain molecular energy level where it will easily boil off into vacuum.

Just some cute little info-bites.

Hard vacuum and Soft vacuum are terms that are defined with a dividing line defined differently by different sources, such as 5 psia[34], one Torr[35], or 0.1 Torr[36] the common denominator being that a hard vacuum is a higher vacuum than a soft one.

Vacuum tube 10 µPa to 10 nPa 10−7 to 10−10

Pressure on the Moon approximately 1 nPa 10−11 4 X 105[37]


Hmmm I need to find a way to add superscript and subscript to this forum. I need more permissions Mark!! :P

[Sam Fraser]

A cool picture:

http://cache-01.gawkerassets.com/assets/images/8/2010/05/ast_themis_hielo_port_imprenta.jpg

Apparently this asteroid is part of a family of rocks that have been traced back to a collision over one billion years ago.